在 C 中为 const char * 分配定义常量 [英] Assign a define constant to const char * in C

问题描述

我不完全确定哪个是将常量分配给 const char * 的正确方法.两种方式都可以吗?

I'm not entirely sure which is the right way to assign a constant to a const char *. Are both ways okay?

#define MSG1 "My Message #1"
#define MSG2 "My Message #2"
#define MSG3 "My Message #3"

const char *opt1 = NULL;
const char opt2[20];

switch(n){
    case 1:
        opt1 = MSG1;
        // or should it be:
        strcpy(opt2, MSG1);
    break;
    case 2:
        opt1 = MSG2;
        // or should it be:
        strcpy(opt2, MSG2);
    break;
    case 3:
        opt1 = MSG3;
        // or should it be:
        strcpy(opt2, MSG3);
    break;

}
// ...
printf("%s", optX);

推荐答案

opt1 = MSG1;

将分配指针opt1指向MSG1指向的字符串.

will assign the pointer opt1 to point to the string literal that MSG1 points.

strcpy(opt2, MSG1);

将MSG1的内容复制到数组opt2中.

will copy the contents of MSG1 to the array opt2.

既然你把opt2声明为const，修改它的内容是非法的，所以第一种方式是正确的.

Since you are declaring opt2 as const, it's illegal to modify the content of it, so the first way is correct.

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